The present invention relates to a method of calibrating power for a MIMO-OFDM transmitter, and more particularly, to a method of calibrating power for a MIMO-OFDM transmitter, by which a MIMO-OFDM signal including CDD is simultaneously output through each antenna of the MIMO-OFDM transmitter and a receiving end simultaneously calibrates power for each antenna by using characteristics of the CDD.
As well known in the art, a multi input and multi output orthogonal frequency division multiplexing (MIMO-OFDM) scheme is used to increase a high data rate of a wireless local area network or long term evolution system. Since MIMO, which is a scheme of transmitting/receiving a signal using multiple antennas, has a plurality of antennas constituting a transmission end thereof, power calibration for each transmission antenna must be performed to exactly measure power of each transmission antenna.
In general, the power calibration for a MIMO-OFDM transmitter is performed by measuring the power level of an input signal through measuring equipment such as a spectrum or signal analyzer and controlling a gain such that the difference between the measured power level and a target power level set at the MIMO-OFDM transmitter is constant.
According to the related art, the power calibration for a MIMO-OFDM transmitter is performed by outputting a continuous wave (CW) tone signal or the same signal input and signal out (SISO) signal and measuring the output power level of the corresponding transmission antenna one by a time, that is, measuring the power levels of each antenna in sequence, the more number of transmission antennas is, the more time taken to perform the power calibration is increased in proportion to the number of transmission antennas.